1. Field of the Invention
The invention relates to a circulating filter and aerator system for use in aquaculture, more particularly to a filter and aerator system which is capable of maintaining the water and soil qualities and which can overcome the drawbacks commonly encountered with the use of underground water sources, such as the use of an excess amount of water to dilute the polluted water and to discharge the same to a clean water source.
2. Description of the Related Art
In a conventional aquaculture system, water from an underground water source is pumped into a pond. A vaned water mill serves as an aerator and is used to introduce air into the water in the pond. In order to prevent the spread of disease, treatment agents are poured into the pond so as to control the growth of plankton and parasites. The main drawbacks of the conventional aquaculture system are as follows:
1. Continuous drawing of water from the underground water source can cause severe environmental damage, such as sinking of the ground, because the amount of water drawn is more than that which can be supplied naturally to the underground water source.
2. Although the vaned water mill can introduce air into the water in the pond, the water mill cannot control the growth Of plankton thereat, thereby resulting in the spread of diseases in the latter.
3. Long term use of treatment agents will not only seriously pollute the water and soil of the aquaculture system, but will also result in immunity from disease causing sources.
In the daily operation of the conventional aquaculture system, an excess amount of water is pumped from the underground source to dilute the water in the pond. This is necessary because the quality of water in the pond gets worse as a result of the accumulation of unused food and excretion by shrimps, fish or other marine animals. Even with the overflow of excess water in order to dilute the polluted water, there is still a need to clean and dry the bottom of the pond after completion of a breeding cycle. When cleaning the bottom of the pond, all of the water in the pond is removed in order to expose the bottom of the pond to the sun so as to decontaminate the same. Soil in the pond bottom is upturned and is exposed to the sunlight, and treatment agents may be added to decompose the waste collected in the soil, before water is pumped back into the pond. Thus, cleaning of the pond bottom requires a lot of time, normally a month or longer, and manpower, thereby resulting in financial loss to the operator of the conventional aquaculture system.